title: O-H anharmonic vibrational motions in Cl(-)···(CH3OH)(1-2) ionic clusters. Combined IRPD experiments and AIMD simulations.
abstract: The structures of Cl(-)-(Methanol)1,2 clusters have been unraveled combining Infrared Predissociation (IR-PD) experiments and DFT-based molecular dynamics simulations (DFT-MD) at 100 K. The dynamical IR spectra extracted from DFT-MD provide the initial 600 cm(-1) large anharmonic red-shift of the O-H stretch from uncomplexed methanol (3682 cm(-1)) to Cl(-)-(Methanol)1 complex (3085 cm(-1)) as observed in the IR-PD experiment, as well as the subtle supplementary blue- and red-shifts of the O-H stretch in Cl(-)-(Methanol)2 depending on the structure. The anharmonic vibrational calculations remarkably provide the 100 cm(-1) O-H blue-shift when the two methanol molecules are simultaneously organized in the anion first hydration shell (conformer 2A), while they provide the 240 cm(-1) O-H red-shift when the second methanol is in the second hydration shell of Cl(-) (conformer 2B). RRKM calculations have also shown that 2A/2B conformers interconvert on a nanosecond time-scale at the estimated 100 K temperature of the clusters formed by evaporative cooling of argon prior to the IR-PD process.
authors.affiliation: Concordia University Wisconsin, 12800 N. Lakeshore Drive, Mequon, WI 53097, USA. Electronic address: jordan.beck@cuw.edu.
authors.forename: Jordan P
authors.initials: JP
authors.lastname: Beck
authors.forename: Alvaro
authors.initials: A
authors.lastname: Cimas
authors.forename: James M
authors.initials: JM
authors.lastname: Lisy
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Gaigeot
mesh_terms: D000838:Anions / Q000737:chemistry; D002713:Chlorine / Q000737:chemistry*; D000432:Methanol / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D009038:Motion; D011789:Quantum Theory; D013055:Spectrophotometry, Infrared
chemical_list: D000838:Anions; D002713:Chlorine; D000432:Methanol
keywords: DFT-MD; Dynamical spectra; IR-PD; Vibrational anharmonicities; Vibrational spectroscopy